This tip demonstrates the different blending functions available with the OpenGL imaging subset. This program demonstrates use of the glBlendEquation() call. The following keys change the selected blend equation function:

'a' -> GL_FUNC_ADD

's' -> GL_FUNC_SUBTRACT

'r' -> GL_FUNC_REVERSE_SUBTRACT

'm' -> GL_MIN 'x' -> GL_MAX

The example is ported from C examples in the OpenGL Programming Guide (known as the "red book").